1. Field of the Invention
The present invention relates to an addition curing type organopolysiloxane and its gel cured product high in resistance to poisoning particularly by solder fluxes.
2. Description of the Prior Art
Conventionally, various techniques are known wherein an addition reaction between an organopolysiloxane having vinyl groups bonded to silicon atoms and an organohydrogenpolysiloxane having hydrogen atoms bonded to silicon atoms in the presence of a platinum catalyst is used to obtain a gel-like resilient body (see, for example, Japanese Patent Publication (Kokoku) Nos. 38992/1980, 41705/1980, and 35932/1984 and Japanese Pre-examination Patent Publication (Kokai) Nos. 143241/1981, 39658/1987, 35655/1988, and 33475/1988.).
Addition reaction type silicone compositions from which such a silicone gel can be obtained are used in many applications, for example, for potting, coating, and encapsulation.
However, along with the recent development of electrical and electronic parts problems have arisen which are conventionally not taken into account. For example, where the above addition curing type composition is used as a protective or insulating material for IC or the like, troubles such as hampering of the curing, uncuring at the interface, and lowering of the hardness occur because of a solder flux remaining on the IC substrate. Occurrence of such troubles is noticeable and causes serious problems particularly in the case of potting materials and coating materials low in hardness.